1. The Field of the Invention
This invention relates to a reverse osmosis system, and particularly to such a system having operation control responsive to the amount of purified water in a purified water storage tank.
2. The Prior Art
A number of reverse osmosis systems particularly suited for home use have been proposed by the prior art for storing purified water produced by a module containing a semipermeable membrane. Various arrangements are described in U.S. Pat. Nos. 3,493,496; 3,746,640; 3,794,172 and 3,794,173. Such systems have employed various methods of controlling operation to provide release of purified water from the storage tank when an excess is produced (often determined by pressure), or simply rely on back pressure build-up in a closed purified water tank to slow down osmotic action and purified water production when the tank is full. Release of excess purified water by overflow is wasteful since the membrane module continues to operate, and the purified water, as well as brine or concentrate, is allowed to flow to drain. Control by allowing pressure build-up of the purified water in the storage tank is not very precise since purified water may continue to flow into the storage tank until shut off pressure is reached, and overflow must often also be provided.
This invention solves the problem of purified water storage tank control in a reverse osmosis system by automatically turning off or on the feed water supply to the membrane module, which correspondingly controls its purified water output, or the purified water supply to the storage tank, to maintain a predetermined amount of purified water in
This invention solves the problem of purified water storage tank control in a reverse osmosis system by automatically turning off or on the feed water supply to the storage tank. This invention does not employ a float valve or other mechanical contrivance inside the purified water storage tank which might be subject to mechanical failure or might corrode and impart an undesirable taste to the contained water.